1. Field of the Invention
The present invention relates to copyright protection of source digital data, and more particularly, to a method of protecting source digital data by inserting a watermark into the source data in a manner that an unintended third party who intercepts an informational medium is not able to determine the presence and the informational content of the watermark.
2. Discussion of the Related Art
Digital multimedia data are widely distributed on the Internet or with the usage of many types of storage such as CD-ROM, hard and floppy disks, and etc. The copyright of the multimedia data has become one of many problems of such distribution processes. One of many ways of protecting any intellectual property right of a multimedia data set is to employ a digital watermark.
The currently existing watermarking techniques base on the representation of source digital or non-digital data in a digital form, which corresponds to a certain domain. The most popular watermarking techniques are spatial-domain and frequency-domain watermarking techniques. The present invention relates to representation of source data an eigen-vector domain, which has never been introduced before.
The main goals of the watermarking methods are non-perceptivity of watermarks and robustness against any attacks. The possible attacks are loose-compression, filtering, re-sampling attacks, and so on. Some of the mentioned goals may contradict with one another because the non-perceptivity means the weak alteration of the source data, and this weak alteration may be eliminated by certain attacks.